Health risks and informal employment in South Africa: does formality protect health?

Background:

The association between work and health has not been well explored in the context of economically developing countries, largely due to inadequate data.

Objectives:

The objective of this study was to identify the association between informal wage work and health in South Africa using a newly available data set that includes detailed information on both employment and health.

Methods:

To explore the relationship between formality, work, and health in South Africa, data from the first (2008) wave of the National Income Dynamic Study (NIDS) were analyzed. We constructed a “formality index” which represents work arrangements on a continuum of formality to informality allowing for a more nuanced analysis of the association between wage work and health.

Results:

We found that formality of employment was significantly associated with health in South Africa, but that the protective effect of formality in employment on health was largely derived from the higher levels of income earned through more formal types of employment. Nevertheless, we did find that the association between informality and poor health was significantly greater for women in wage employment than for males.     

Metabolic activation of aromatic hydrocarbons in purified rat liver nuclei: induction of enzyme activities and binding to DNA with and without monooxygenase-catalyzed formation of active oxygen.

Purified rat liver nuclei covalently bound low levels of seven aromatic [14C]hydrocarbons to nuclear DNA. Induction with 3-methylcholanthrene increased the binding of six carcinogenic hydorcarbons, but did not raise the level of binding of noncarcinogenic anthracence. Removal of the nuclear envelope by Triton N-101 eliminated binding and aryl hydrocarbon hydroxylase activities and cytochrome P-450 from the nuclei. Binding of two of two strong carcinogens, benzo[a]pyrene and 7,12-dimethylbenz[a]anthracene, to nuclear DNA was compared to the levels of aryl hydrocarbon hydroxylase and cytochrome P-450 in nuclei from uninduced and benz[a]anthracene-, 3-methylcholanthrene-, and phenobarbital-induced rats. Microsomal hydroxylase and cytochrome P-450 were also assayed. Induction with 3-methylcholanthrene gave the largest increases in nuclear activities: 11 times as much hydroxylase, 6 times as much cytochrome P-450, and 4 times as much binding of both hydrocarbons. Benz[a]anthracene and phenobarbital induced these nuclear activities 0- to 4-fold. In the presence of added NADPH, binding of benzol[a]pyrene to DNA by nuclei increased rapidly for at least 20 min. When NADPH was not added, the reaction stopped at a low level in 5 min. When CO was bubbled through the reaction mixture with or without added NADPH, binding of benzo[a]pyrene and 7,12-dimethylbenz[a]anthracene was partially inhibited, indicating that cytochrome P-450 plays a role in this activation. Since no nuclear hydroxylase activity was seen without added NADPH or in the presence of CO, activation and subsequent binding of hydrocarbons to nuclear DNA, at least in part, does not require the activated oxygen used in monooxygenase reactions.     

A study of body weight concerns and weight control practices of 4th and 7th grade adolescents

Objective. The purpose of this study was to assess grade, race, socioeconomic status and gender differences in perceptions of body size, weight concerns, and weight control practices between 4th and 7th grade students in South Carolina. Design. Two random samples, consisting of a total of 1,597 children (53.1% white, 51.97% female, 44.9% 4th graders) participated in two questionnaire surveys. Both surveys included a series of seven female and seven male body size drawings, body image and weight concern questions, and questions pertaining to weight control practices. Responses to the questionnaire were analyzed using chi-square analysis and the General Linear Model. Results. Using socioeconomic status (SES), race, gender, and grade as independent variables, differences in ideal adult body size, opposite gender ideal adult body size, weight concerns, perceptions of family/peer weight concerns, perceptions of own body size and weight control practices were studied. Analyses revealed that 4th grade males select a larger ideal adult body size and opposite gender ideal adult body size when compared to 7th grade males ( p < 0.0001 and p = 0.0078, respectively). Fourth grade females indicated less personal concern about their weight than 7th grade females ( p = 0.0009). Fourth graders also perceived less family/peer concern about weight than 7th graders ( p = 0.0027) and 7th graders described themselves as being more overweight than 4th graders ( p = 0.0039). Blacks selected a significantly larger body size than white children for ideal adult ( p = 0.0287) and ideal opposite gender adult body size ( p < 0.0001 for males, p = 0.0030 for females). Blacks also perceived less personal and family/peer concern about weight when compared to whites ( p = 0.0083). More whites reported that they were trying to lose weight, as compared to blacks ( p = 0.0010). Males also selected significantly larger body size silhouettes than females for ideal adult body size ( p = 0.0012). Males expressed less personal concern about weight ( p < 0.0001), perceived less family/peer concern about weight ( p < 0.0001), and were less likely than females to be engaged in weight loss ( p < 0.0001). Females in the high SES category selected a significantly smaller ideal male adult body size than females in the low SES group ( p = 0.0124) and more females in the high SES category were trying to lose weight when compared to females in the low SES group ( p = 0.0055).) Conclusion. This study indicates that early in a child's sociocultural development, grade level, gender, race, and SES are influential in the perception of ideal adult body size and opposite gender ideal adult body size. These factors are also influential in determining concerns about weight and weight control practices. The findings of this study support the need to begin health and wellness education efforts early in childhood while taking into account racial, gender, age, and SES disparities. This knowledge can also be useful in targeting interventions for both obesity and eating disorders.     

Synthesis and tumor-initiating activity in mouse skin of dibenzo[a,l]pyrene syn- and anti-fjord-region diolepoxides

Dibenzo[a,l]pyrene (DB[a,l]P) is the most potent carcinogenamong polycycic aromatic hydrocarbons. Because the fjord-regiondiolepoxide (DE) pathway is one of the mech anisms of activation,(±)-trans-DB [a,l]P-11,12-dihydrodiol,(±)-anti-DB[a,l]PDEand (±)-syn-DB[a,l]PDE were synthesized. The key intermediatefor these syntheses, 12-methoxy-DB[a,l]P, was successfully obtainedby cyclizatlon of 6-(3-methoxybenzyl)benzanthrone with methanesulfonicacid, which in turn was prepared by 1,4 conjugate addition of3-methoxybenzyl magnesium bromide to benzanthrone. The presenceof the DB[a,l]P nucleus in the dihydrodiol epoxides and diolepoxideswas proven by conversion of 12-methoxyDB[a,l]P into the parentcompound in several steps. The tumor-initiating activity ofthe two diolepoxides in mouse skin was compared to that of DB[a,l]P-11,12-dihydrodioland the parent DB[a,l]P Groups of 24 8 week old female SENCARmice were topically initiated with 12, 4 or 133 nmol of compoundIn 100 µl of acetone. Starting 1 week later, promotionwith 12-O-tetradecanoylphorbol-13-acetate (1.62 nmol In 100µl acetone) was begun and continued twice weekly for 30weeks. At the 12, 4 and 1.33 nmol doses, anti-DB[a,l]PDE induced2.0, 0.7 and 0.7 tumors per mouse (t/m) respectively, whereassyn DB[a,l]PDE induced 1.8, 1.5 and 1.8 t/m. At the same threedoses, DB[a,l]P-11,12-dihydrodiol induced 4.6, 4.3 and 2.8 t/m,and DB[a,l]P resulted in 9.3,7.1 and 5.2 t/m. These resultsconfirm that DB[a,l]P is more potent than its 11,12-dihydrodloland show that the two diolepoxides are less tumorlgenic thantheir precursors. At the medium and low doses, syn-DB[a,l]PDEis more tumorigenic than its congener anti-DB[a,l]PDE.     

Corneal flap displacement and drift in LASIK: comparison of Hansatome and Automated Corneal Shaper microkeratomes

PURPOSE: To describe and compare the displacement of corneal flaps created during laser in situ keratomileusis (LASIK) procedures performed with two different microkeratomes and analyze parameters (for example, pupil-to-hinge distance, drift during suction) that might affect the flap displacement or be influenced by flap displacement. DESIGN: This work was based on a cross-sectional study design. METHODS: Images copied from video recordings of 206 consecutive LASIK surgeries were analyzed to determine the distance from pupil center to corneal flap hinge (pupil-to-hinge distance), the hinge size, the distance from the center of the pupil to the margins of the flap, and the positions of the suction ring before and after vacuum in corneal flaps created by the Hansatome and the Automated Corneal Shaper (ACS) microkeratomes. Accurate measurements of all these variables could be obtained in 121 eyes (Hansatome: n = 66, right eye (OD) = 27 eyes, left eye (OS) = 39 eyes; ACS: n = 55, OD = 25 eyes, OS = 30 eyes), which were included in the analysis. Formulas were derived to calculate from the measurements the magnitude and direction of the drift of the suction ring during vacuum and the final displacement of the corneal flap. RESULTS: The mean +/- standard deviation (SD) drift of eyes during suction with the Hansatome was 0.27 +/- 0.02 mm and with the ACS was 0.12 +/- 0.02 mm (P <.001). The Hansatome induced, on average, more biased (temporal vs random) drift than did the ACS. The mean final displacement of the center of the flap from the center of the pupil was of equal magnitude for the two instruments (0.37 +/- 0.02 mm and 0.36 +/- 0.02 mm with the Hansatome and ACS, respectively). CONCLUSION: The drift induced by the Hansatome contributes to the horizontal component of the final decentration of the corneal flaps. This tendency for drift and the resultant decrease in pupil-to-hinge distance should be considered to minimize flap displacements during LASIK.     

Deficiency of either cyclooxygenase (COX)-1 or COX-2 alters epidermal differentiation and reduces mouse skin tumorigenesis

Nonsteroidal anti-inflammatory drugs are widely reported to inhibit carcinogenesis in humans and in rodents. These drugs are believed to act by inhibiting one or both of the known isoforms of cyclooxygenase (COX). However, COX-2, and not COX-1, is the isoform most frequently reported to have a key role in tumor development. Here we report that homozygous deficiency of either COX-1 or COX-2 reduces skin tumorigenesis by 75% in a multistage mouse skin model. Reduced tumorigenesis was observed even though the levels of stable 7,12-dimethylbenz(a)anthracene-DNA adducts were increased about 2-fold in the COX-deficient mice compared with wild-type mice. The premature onset of keratinocyte terminal differentiation appeared to be the cellular event leading to the reduced tumorigenesis because keratin 1 and keratin 10, two keratins that indicate the commitment of keratinocytes to differentiate, were expressed 8-13-fold and 10-20-fold more frequently in epidermal basal cells of the COX-1-deficient and COX-2-deficient mice, respectively, than in wild-type mice. Papillomas on the COX-deficient mice also displayed the premature onset of keratinocyte terminal differentiation. However, loricrin, a late marker of epidermal differentiation, was not significantly altered, suggesting that it was the early stages of keratinocyte differentiation that were primarily affected by COX deficiency. Because keratin 5, a keratin associated with basal cells, was detected differently in papillomas of COX-1-deficient as compared with COX-2-deficient mice, it appears that the isoforms do not have identical roles in papilloma development. Interestingly, apoptosis, a cellular process associated with nonsteroidal anti-inflammatory drug-induced inhibition of tumorigenesis, was not significantly altered in the epidermis or in papillomas of the COX-deficient mice. Thus, both COX-1 and COX-2 have roles in keratinocyte differentiation, and we propose that the absence of either isoform causes premature terminal differentiation of initiated keratinocytes and reduced tumor formation.     

Splice variants but not mutations of DNA polymerase beta are common in bladder cancer

DNA polymerase beta (POLbeta) is a highly conserved protein that functions in base excision repair. Loss of the POLbeta locus on chromosome 8p is a frequent event in bladder cancer, and loss of POLbeta function could hinder DNA repair leading to a mutator phenotype. Both point mutations and large intragenic deletions of POLbeta have been reported from analysis of various tumor cDNAs but not from genomic DNA. We noticed that the breakpoints of the presumed rearrangements were delineated by exon-exon junctions, which could instead be consistent with alternative splicing of POLbeta mRNA. We tested the hypothesis that the reported intragenic deletion were splice variants by screening genomic DNA of human bladder tumors, bladder cancer cell lines, and normal bladder tissues for mutations or deletions in exons 1-14, exon alpha, and the promoter region of POLbeta. We found no evidence of somatic mutations or deletions in our sample set, although two polymorphisms were identified. Examination of cDNA from a subset of the original sample set revealed that truncated forms of POLbeta were surprisingly common. Forty-eight of 89 (54%) sequenced cDNA clones had large deletions, each beginning and/or ending exactly at exon-exon junctions. Because these deletions occur at exon-exon junctions and are seen in cDNA but not genomic DNA, they are consistent with alternative mRNA splicing. We describe 12 different splicing events occurring in 18 different combinations. Loss of exon 2 was the most frequent, being found in 42 of 49 (86%) of the variant sequenced clones. The splice variants appear to be somewhat more common and variable in bladder cancer cell lines and tumor tissues but occur at a high frequency in normal bladder tissues as well. We examine alternative splicing in terms of the information content of splice donor and acceptor site sequences, and discuss possible explanations for the predominant splicing event, the loss of exon 2.     

Thalidomide use in the US : experience with pregnancy testing in the S.T.E.P.S. programme.

INTRODUCTION: In 1998, thalidomide (Thalomid), a known human teratogen, was approved by the US FDA for the treatment of erythema nodosum leprosum. To prevent fetal exposure to thalidomide, a restricted distribution risk management programme, the System for Thalidomide Education and Prescribing Safety (S.T.E.P.S.), was implemented. All clinicians, pharmacists and patients who prescribe, dispense and receive thalidomide, respectively, are required to enroll in S.T.E.P.S. Sexually active females of childbearing potential must use two methods of birth control before, during and after treatment. These patients must also have a negative pregnancy test within 24 hours before beginning therapy and periodically while on therapy. The objective of this report is to summarise the patterns of thalidomide use and to describe the occurrence of positive pregnancy tests in females of childbearing potential while they were using thalidomide in the S.T.E.P.S. programme in the US. STUDY DESIGN/METHODS: A retrospective review of patients receiving thalidomide within the S.T.E.P.S. programme from September 1998 to 31 December 2004 to determine the occurrence of positive pregnancy tests whilst on treatment. RESULTS: Approximately 124,000 (43% female) patients were registered within the S.T.E.P.S. programme between September 1998 and 31 December 2004. Approximately 6,000 patients were females of childbearing potential, representing 5% of all patients and 11% of all female patients. Between 30 July 2001 and 31 December 2004, >88% of thalidomide use was for oncological conditions. There were 72 females of childbearing potential who had positive pregnancy tests. Sixty-nine of these patients had false positive pregnancy tests. Of the remaining three, one woman was pregnant while on thalidomide. This patient had an initial negative test and received thalidomide. Therapy was stopped when she had a positive pregnancy test. This pregnancy resulted in a miscarriage. Two additional patients were determined to be pregnant before receiving thalidomide. CONCLUSIONS: The S.T.E.P.S. programme is critical to managing the risks of thalidomide-associated teratogenicity. Sustained vigilance among health care providers and patients receiving thalidomide is essential to its continued success. Health care providers should be aware of the occurrence of false-positive pregnancy tests in females of childbearing potential receiving thalidomide.